PVEL has not identified any catastrophic failures during BDS testing.
Over the past three years, PVEL’s BDS testing for PQPs has not revealed any backsheets that have suffered from backsheet cracks. This covers backsheets with a range of outer layer materials including coatings, PVF, PVDF and PET films.
PVEL’s BDS test has qualified ~40% of the available backsheets.
The BDS results represent less than half of the 130 backsheets available on the market according to ENF’s solar backsheet directory. It is possible that the untested backsheets, including those from new market entrants, are susceptible to cracking.
Electrical insulation and power label failures exist.
While no cracking has been observed, PVEL has detected wet leakage/electrical insulation failures during BDS that were traced to the junction boxes. Additionally, UV exposure made some power labels illegible, a major defect according to IEC 61215.
Historical modules still suffer from backsheet failures.
PVEL is frequently contacted by site owners experiencing insulation failures, delamination, and corrosion issues due to modules with backsheet cracks. Repairs are often the suggested remedy, the reliability of which remains unclear.